paint cracking

[Blue Meanie]

I noticed an area where the paint looks like it is starting to crack on my roof. Apparently I didn't sand well enough during prep. Does anyone know of a good compound or wax I can buff into it, so I can "hide" it till garage season and get it done right? It's hard to see, but I know it is there and it is driving me nuts!

Thanks all.

[MikeW]

Where is the crack? It's common to have cracks on both sides where the roof panel is joined to the quarter panel.

[Sailor Bob]

Good tip Mike - I have been trying to figure why my car has touch up paint on both sides around there, hard to imagine damage on both sides? - Question answered.

Later

[MikeW]

That particular problem is caused by the factory joint using lead solder. When the body of the car flexes the paint cracks. My body guy removed the lead and replaced it with a modern panel bond adhesive. Here's an old thread that describes the problem better than I can:

http://www.classiczcars.com/forums/showthread.php?t=6190

[Blue Meanie]

middle of the roof unfortunately.

[Mat M]

I'd like to see an answer posed, as well. The pass. door has all kinds of crackling paint, but the paint won't flake off.

[EScanlon]

Cracking ... or .... crazing?

A crack is just that, a visible break in the paint. Sometimes in a straight line and sometimes in a curve but generally with a distinct edge to it's edge.

Crazing on the other hand, can look like cracking, except now it starts to look more like shattered safety glass. That is, a cross-hatch pattern composed of various "lines" of cracks that criss-cross each other in irregular pieces but mostly rectangular shaped (or an angled parallelogram).

Cracking is generally caused by flexing of the sub metal or joint and the paint not flexing to the same degree.

Crazing on the other hand is usually indicative of a poor prep job prior to paint. Causes can be body oils, poorly cured red-cap or too thick primer or some other incompatibility with the base primer or filler or...

Cracking can sometimes be masked by careful application of touch up paint.

Crazing can also be masked with touch up paint, but usually will craze again.

Crazing can also look like a stress crack on the paint on a rubber bumper.

FWIW

E

[Blue Meanie]

I think I'm riding the crazing train.